Introduce window container to be used by lock screen app windows

ash/public/cpp/shell_window_ids.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_PUBLIC_CPP_SHELL_WINDOW_IDS_H_
 #define ASH_PUBLIC_CPP_SHELL_WINDOW_IDS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 95 matching lines @@
   // ID of the window created by PhantomWindowController or
   // DragWindowController.
   kShellWindowId_PhantomWindow,
 
   // The container for mouse cursor.
   kShellWindowId_MouseCursorContainer,
 
   // The topmost container, used for power off animation.
   kShellWindowId_PowerButtonAnimationContainer,
 
+  // The containers for windows that handle lock tray actions (e.g. new note
+  // action). The action handler windows containers should be visible on lock
+  // screen, but only when an action is being handled. The container to which
+  // the action handler window should be added depends on the lock action state:
+  // * in active state, the window should be contained in
+  //   LockActionHandlerContainer, which is stacked over lock screen container.
+  // * in background state, the window should be container in
+  //   LockActinHandlerContainer_Background, which is stacked below lock screen
+  //   container.
+  kShellWindowId_LockActionHandlerContainer,
+  kShellWindowId_LockActionHandlerContainer_Background,
+
   kShellWindowId_Min = kShellWindowId_ScreenRotationContainer,
-  kShellWindowId_Max = kShellWindowId_PowerButtonAnimationContainer,
+  kShellWindowId_Max = kShellWindowId_LockActionHandlerContainer_Background,
 };
 
 // A list of all the above valid container IDs. Add any new ID to this list.
 // This list is needed to validate we have no duplicate IDs.
 const int32_t kAllShellContainerIds[] = {
     kShellWindowId_ScreenRotationContainer,
     kShellWindowId_NonLockScreenContainersContainer,
     kShellWindowId_LockScreenContainersContainer,
     kShellWindowId_LockScreenRelatedContainersContainer,
     kShellWindowId_UnparentedControlContainer,
@@ skipping 11 matching lines @@
     kShellWindowId_LockSystemModalContainer,
     kShellWindowId_StatusContainer,
     kShellWindowId_ImeWindowParentContainer,
     kShellWindowId_MenuContainer,
     kShellWindowId_DragImageAndTooltipContainer,
     kShellWindowId_SettingBubbleContainer,
     kShellWindowId_OverlayContainer,
     kShellWindowId_PhantomWindow,
     kShellWindowId_MouseCursorContainer,
     kShellWindowId_PowerButtonAnimationContainer,
+    kShellWindowId_LockActionHandlerContainer,
+    kShellWindowId_LockActionHandlerContainer_Background,
 };
 
 // These are the list of container ids of containers which may contain windows
 // that need to be activated.
 ASH_PUBLIC_EXPORT extern const int32_t kActivatableShellWindowIds[];
 ASH_PUBLIC_EXPORT extern const size_t kNumActivatableShellWindowIds;
 
 // Returns true if |id| is in |kActivatableShellWindowIds|.
 ASH_PUBLIC_EXPORT bool IsActivatableShellWindowId(int32_t id);
 
 }  // namespace ash
 
 #endif  // ASH_PUBLIC_CPP_SHELL_WINDOW_IDS_H_